Low-force electrochemical mechanical processing method and apparatus

ABSTRACT

The present invention relates to semiconductor integrated circuit technology and discloses an electrochemical mechanical processing system for uniformly distributing an applied force to a workpiece surface. The system includes a workpiece carrier for positioning or holding the workpiece surface and a workpiece-surface-influencing-device (WSID). The WSID is used to uniformly distribute the applied force to the workpiece surface and includes various layers that are used to process and apply a uniform and global force to the workpiece surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S.Provisional Application Serial No. 60/326,087 filed Sep. 28, 2001.

FIELD OF THE INVENTION

[0002] The present invention relates generally to semiconductorintegrated circuit technology and, more particularly, to electrotreatingor electrochemical apparatus and processing techniques such aselectroplating and electroetching that are applied to a workpiecesurface.

BACKGROUND OF THE INVENTION

[0003] Conventional semiconductor devices such as integrated circuits(IC) generally include a semiconductor substrate, usually a siliconsubstrate, and several sequentially formed conductive material layersseparated by insulating material layers. Conductive material layers, orinterconnects, form the wiring structure of the IC. A wiring structureis isolated from the neighboring wiring structures by insulating layersor interlayer dielectrics. A dielectric material that is commonly usedin silicon ICs is silicon dioxide, although there is a current trend toreplace at least some of the standard dense silicon dioxide material inthe IC structure with low-k dielectric materials. This replacement isnecessary in high performance ICs where the RC time constant needs to bereduced to increase the speed of the circuit. To reduce the capacitance,the high dielectric constant materials in the interconnect structureneeds to be replaced with low-k materials.

[0004] There are various low-k materials that have been used in theindustry. These are organic, inorganic, spin-on and CVD materials. Somelow-k materials are porous with dielectric constants well below 3.0. Asis well known, implementing low-k dielectrics presents manymanufacturing challenges. For example, their low mechanical strengthand/or poor adhesion to the substrate present some challenges in thesemiconductor industry.

[0005] IC interconnects are formed by filling a conductor such as copperin features or cavities etched into the dielectric interlayers by ametallization process. Copper is becoming the preferred conductor forinterconnect applications because of its low electrical resistance anddesired electromigration property. Currently, electroplating is thepreferred process for copper metallization.

[0006] In the typical IC, multiple levels of interconnect structuresextend laterally with respect to the substrate surface. Interconnectsformed in sequential layers can be electrically connected using featuressuch as vias or contacts. In a typical interconnect fabrication process,an insulating layer is first formed on the semiconductor substrate.Patterning and etching processes are then performed to form features orcavities such as trenches, vias, and pads etc., in the insulating layer.Then, copper is electroplated to fill the features. In suchelectroplating process, the workpiece or wafer (these terms are usedinterchangeably herein) is placed on a wafer carrier and a cathodic (−)voltage with respect to an electrode is applied to the wafer surfacewhile the electrolyte or the electrolyte solution wets both the wafersurface and the electrode.

[0007] Once the plating process is over, a material removal step such asa chemical mechanical polishing (CMP) process is performed to remove theexcess copper layer (also called copper overburden) from the topsurfaces (also called field region) of the wafer, thereby leaving copperonly within the features. An additional material removal step is thenperformed to remove other conductive layers such as the barrier/gluelayers that are on the field regions. In this manner, deposited copperwithin the features are physically as well as electrically isolated fromeach other. It should be noted that material removal processes include,but are not limited to, CMP, electroetching and etching processes.Furthermore, processes for removing both copper and barrier/glue layersfrom the field regions in one step may also be employed.

[0008] During CMP, the plated wafer surface is pressed on a movingpolishing pad or a polishing belt and planarized while the wafer isrotated. As mentioned above, this process electrically isolates thecopper deposited into various features on a given interconnect level.After repeating these processes several times, multi-level interconnectstructures may be formed in which copper within via or contact featuresmay electrically connect the various interconnect levels. However, theCMP processes can create problems with low-k dielectrics because of themechanical force applied on the wafer surface during the processes. Forinstance, during CMP, the low-k materials may be stressed and delaminateor other defects may result due to the low mechanical strength or pooradhesion of the low-k materials. The longer the CMP process, theseproblems become more prominent. Accordingly, it is desirable to reducethe CMP time and force applied on the wafers, especially those usinglow-k insulators.

[0009] There are efforts to lower the force or pressure used in CMPprocesses. There is also efforts to employ etching or electroetchingtechniques instead of CMP to remove the copper overburden from the fieldregions of plated substrates.

[0010] The adverse effects of CMP may be minimized or overcome byemploying a planar copper deposition approach that can provide thinlayers of planar copper on the workpiece surface. One such planardeposition technique is the Electrochemical Mechanical Deposition (ECMD)method. In one aspect of ECMD, a workpiece-surface-influencing device(WSID) such as a mask, pad or a sweeper is used during at least aportion of the electrodeposition process when there is physical contactand relative motion between the workpiece surface and the WSID.Descriptions of various planar deposition methods and apparatus can befound in the following patents and pending applications, all commonlyowned by the assignee of the present invention: U.S. Pat. No. 6,176,992entitled “Method and Apparatus for Electrochemical MechanicalDeposition”; U. S. application Ser. No. 09/740,701 entitled “PlatingMethod and Apparatus that Creates a Differential Between AdditiveDisposed on a Top Surface and a Cavity Surface of a Workpiece Using anExternal Influence,” filed on Dec. 18, 2001; and U.S. application Ser.No. 09/961,193 entitled “Plating Method and Apparatus for ControllingDeposition on Predetermined Portions of a Workpiece,” filed on Sep. 20,2001. The methods disclosed in these patent/applications can be used todeposit metals in and over cavity sections on a workpiece in a planarmanner.

[0011] Using ECMD methods, the workpiece surface is wetted by theelectrolyte and is rendered cathodic with respect to an electrode, whichis also wetted by the electrolyte. This results in material depositionon the surface of the workpiece. These techniques can also be used forelectroetching by reversing the polarity of the applied voltage andrendering the workpiece surface more anodic compared to the electrode.Very thin planar deposits can be obtained by first depositing a planarlayer using an ECMD technique and then electroetching this planar filmin the same electrolyte or in a special electro-etching orelectro-polishing solution by reversing the applied voltage. In thismanner, the thickness of the deposited layer may be reduced in a planarmanner. In fact, this etching process can occur until all/most of themetal on the field regions are removed. It should be noted that a WSIDmay or may not be used during the electroetching process since planaretching can be achieved with or without the WSID.

[0012] In greater detail, during ECMD, the workpiece surface is pushedagainst the surface of the WSID or vice versa for at least portion ofthe time when the surface of the workpiece is swept by the WSID. Planardeposition occurs due to the sweeping action as described above. It isalso desirable to reduce the force applied on the workpiece surface bythe sweeper surface, especially for workpieces with structurally weaklow-k materials. When the force is reduced, however, the integrity ofthe contact between the workpiece surface and the sweeper surface needto be preserved. In other words, this physical contact needs to beuniform and repeatable for optimal results. Accordingly, there is needfor an improved ECMD method and apparatus for minimizing the forceapplied to the substrate surfaces during planar metal deposition orelectroetching while keeping this force uniformly distributed over thesweeper area.

SUMMARY OF THE INVENTION

[0013] The present invention discloses an electrochemical mechanicalprocessing system for uniformly distributing an applied force to aworkpiece surface. The system includes a workpiece carrier forpositioning or holding the workpiece surface and aworkpiece-surface-influencing-device (WSID). The WSID is used touniformly distribute the applied force to the workpiece surface andincludes, in one embodiment, a flexible top layer, a rigid bottom layer,and a compressible intermediate layer disposed in between the top layerand the bottom layer. The flexible top layer makes contact with theworkpiece surface. The flexible top layer can be a single layer or acomposite layer. The composite layer can further include an abrasiveupper layer and a lower layer.

[0014] In another embodiment, the present invention discloses a systemthat includes a WSID having a first compressible layer and a secondcompressible layer, a rigid support layer disposed in between the firstand second compressible layers, and a flexible layer attached to thefirst compressible layer, where the flexible layer makes contact withthe workpiece surface.

[0015] Additional embodiments are disclosed in the present invention andare described in greater detail below, including methods for using thepresent invention.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0016] These and other objects and advantages of the present inventionwill become apparent and more readily appreciated from the followingdetailed descriptions of the presently preferred embodiments of theinvention taken in conjunction with the accompanying drawings, of which:

[0017]FIG. 1A illustrates a conventional electrochemical mechanicalprocessing system;

[0018]FIG. 1B illustrates a section of a wafer in contact with aconventional sweeper structure;

[0019]FIG. 1C illustrates a section of a wafer in contact with a sweeperstructure in accordance with the present invention;

[0020]FIG. 2A illustrates a more detailed section of a conventionalwafer surface;

[0021]FIG. 2B illustrates the wafer surface of FIG. 2A having a planarcopper layer deposited thereon;

[0022]FIG. 3A illustrates a workpiece-surface-influencing device inaccordance with the present invention;

[0023]FIG. 3B illustrates a perspective view of theworkpiece-surface-influencing device in accordance with the presentinvention;

[0024]FIG. 3C illustrates the workpiece-surface-influencing deviceduring operation in accordance with the present invention;

[0025]FIG. 3D illustrates an example of a composite layer structure ofthe workpiece-surface-influencing device in accordance with the presentinvention;

[0026]FIG. 3E illustrates another example of a wafer carrier inaccordance with the present invention;

[0027]FIG. 4 illustrates another example of aworkpiece-surface-influencing device in accordance with the presentinvention;

[0028]FIGS. 5A and 5B illustrate yet another example of aworkpiece-surface-influencing device in accordance with the presentinvention;

[0029]FIG. 6 illustrates still another example of theworkpiece-surface-influencing device in accordance with the presentinvention;

[0030]FIGS. 7A and 7B illustrate yet another example of aworkpiece-surface-influencing device in accordance with the presentinvention;

[0031]FIG. 7C illustrates an example of a top layer structure of theworkpiece-surface-influencing device in accordance with the presentinvention;

[0032]FIGS. 7D and 7E illustrate top and bottom films, respectively, ofthe top layer structure of FIG. 7C in accordance with the presentinvention;

[0033] FIGS. 8A-8C illustrates an example of a non-uniform layer formedon a substrate using a conventional workpiece-surface-influencingdevice; and

[0034]FIGS. 8D and 8E illustrates an example of an uniform layer formedon a substrate using a workpiece-surface-influencing device of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The present invention will now be described in greater detail,which will serve to further the understanding of the preferredembodiments of the invention. As described elsewhere herein, variousrefinements and substitutions of the various embodiments are possiblebased on the principles and teachings herein.

[0036] The preferred embodiments or the present invention will bedescribed with reference to FIGS. 1-8, wherein like components,structures, layers, etc. are designated by like reference numbersthroughout the various figures. Further, specific parameters areprovided herein, which are intended to be explanatory rather thanlimiting.

[0037] The preferred embodiments will be described using the example offabricating interconnects for integrated circuit applications. It shouldbe noted that present invention can be used to fill recesses, alsoreferred to as cavities, on any workpiece having various electroplatedmaterials, such as Au, Ag, Ni, Pt, Pd, Fe, Sn, Cr, Pb, Zn, Co and theiralloys. The cavities can be filled with the above-mentioned materials,and different applications such as packaging, flat panel displays, andmagnetic heads can be used with the present invention.

[0038] In one embodiment of the present invention, a planar conductivelayer is formed on a wafer surface by a low-force ECMD process using anovel workpiece-surface-influencing device (WSID) structure, whichapplies a uniform and low force to the wafer surface. Other structuresmay also be formed using low-force electrochemical mechanical etching(ECME) process. In the following descriptions, both ECMD and ECMEprocesses are referred to as electrochemical mechanical processing(ECMPR) since both processes involve electrochemical processes andmechanical action.

[0039]FIG. 1A illustrates a conventional electrochemical mechanicalprocessing system that can be used in accordance with the presentinvention. The ECMPR system 10 includes a conventional WSID 12 havingopenings 15 disposed in close proximity to a workpiece or wafer 16. Asupport plate 13, which may be porous, supporting the WSID 12 includesopenings or perforations 14. In this example, showing ECMD, the wafer 16is a silicon wafer, which is to be plated with a conductor metal such ascopper or copper alloy. A wafer carrier 18 holds the wafer 16 such thatthe front surface 20 of the wafer 16 is positioned against the topsurface 22 of the WSID 12. The openings 15 are designed to assureuniform deposition of copper from an electrolyte solution 24 onto thefront surface 20. If electroetching, or ECME is used, uniformelectroetching from the front surface 20 will occur, using either adeposition solution or an electroyte solution or an etching solution oran electrolyte solution. The top surface 22 of the WSID 12 facing thefront surface 20 of the wafer 16 is used as the sweeper and the WSID 12itself establishes solution and electric field flows to the frontsurface 20 for global and uniform deposition or etching.

[0040] The ECMPR system 10 also includes an electrode 26, which isimmersed in the solution 24. The solution 24 is in fluid communicationwith the electrode 26 and the front surface 20 of the wafer 16 throughthe openings 15 in the WSID 12. The electrode 26 is typically a Cumaterial for Cu deposition. The electrode 26 may also be an inertelectrode made of, for example, Pt coated Ti. An exemplary copperelectrolyte solution may be copper sulfate solution with additives suchas accelerators, suppressors, leveler, chloride and such, which arecommonly used in the industry.

[0041] During operation, the top surface 22 of the WSID 12 sweeps thefront surface 20 of the wafer 16 at least during part of the process. Itshould be noted that WSID 12 does not have to make contact at all timesduring ECMPR. For deposition of a planar film such as copper, the frontsurface 20 of the wafer 16 is made more cathodic (negative) compared tothe electrode 26, which becomes the anode. For electroetching, the wafersurface is made more anodic than the electrode 26.

[0042] The WSID 12 may include a top layer 28, an intermediate layer 30,and a bottom layer 32. The top layer 28 may be made of an abrasivematerial such as a fixed-abrasive-film supplied by the 3M company or anyof the other so-called pad materials used in CMP applications, such asthe polymeric IC-1000 material supplied by Rodel. The thickness of thetop layer 28 may be typically in the range of 0.1-2.0 mm. Next, theintermediate layer 30 is the mounting layer for the top layer 28. Theintermediate layer 30 is typically made of a hard plastic material suchas polycarbonate with a thickness range of 1.0-3.0 mm. Finally, thebottom layer 32 is used as a compression layer for the completestructure. The bottom layer 32 is generally made of a polymeric foammaterial such as polyurethane or polypropylene with typical compressionstrength that requires about 10-20 psi of pressure to deflect the foamby about 25% of its original thickness, which typically may be in therange of 2.0-5.0 mm. The U.S. application Ser. No. 09/960,236 filed onSep. 20, 2001, entitled “Mask Plate Design,” also assigned to the sameassignee as the present invention, discloses various WSID embodiments.

[0043] As previously mentioned in the Background Section, althoughplanar deposition of thin conductor layers, such as thin copper layers,is attractive for low-k dielectric applications, substrates containinglow-k materials should not be subjected to high-stress. The conventionalWSID 12 may be used for processing wafers with low-k dielectrics byreducing the pressure at which the wafer surface is pushed against theWSID 12. Thus, pressure may be reduced to so as not to damage the low-kmaterials. However, as the overall pressure in the ECMPR system 10 isreduced, this may not necessarily eliminate the possibility of highlocal pressure points on the wafer 16. The WSID 12 is a globallyflexible structure due to the existence of the bottom layer 32, which isa relatively hard foam, but it is not necessarily locally flexible dueto the presence of the intermediate layer 30. In the case of arelatively thick top layer (thicker than 0.5 mm.), the overall rigidityof the WSID structure is increased. The WSID 12 shown in FIG. 1Aprovides global and uniform contact between the surface of the WSID 12and the front surface 20 of the wafer 16. However, locally, thesituation may be different. If the flatness of the WSID 12 and the frontsurface 20 of the wafer 16 is not perfectly flat or these two surfacesare not perfectly parallel, then some surfaces on the wafer 16 will beexposed to higher pressure than the other surfaces during processing,especially when the surface of the wafer 16 is first brought intocontact with the surface of the WSID 12. If, for example, theparallelism is not absolute, as the wafer surface is lowered onto thesweeper surface, one section of the wafer surface may initially contactthe sweeper surface. This section of the wafer surface is then exposedto higher pressure since the applied force is constant and the sweeperis rigid.

[0044]FIG. 1B illustrates a section of a wafer in contact with aconventional sweeper structure. In FIG. 1B, an exemplary section of thewafer 16 is in contact with the sweeper structure 16A. As shown, thewafer 16 may have a non-flat top surface 20. The top surface 20 maycomprise a field region, and the field region may contain thereinrecesses or cavities. The top surface may or may not contain an alreadydeposited conductive layer. This non-flat surface can be caused by anumber of factors, including bowing of or other stress applied to thewafer as it is being held by a wafer carrier, lack of parallelismbetween the sweeper structure 16A and the wafer 16, or non-flattopography of the field region.

[0045] When the conventional sweeper structure 16A is used to processthe wafer 16, the contact area between some sections of the wafersurface 20 and the sweeper surface are not uniform, and thus thepressure is non-uniform. Particularly, in sections 16B, a gap existsbetween the wafer surface 20 and the sweeper surface 16C, and thepressure applied to the wafer surface at this section is nonexistent.This results in non-uniformity in sweeping efficiency over the entirewafer surface with high pressure points at locations where the wafersurface makes contact with the sweeper surface. In addition, defects maybe present as a result. Local high force application on the wafersurface may also result in stressed and peeled areas especially if thewafer surface has mechanically weak layers such as low-k materials.

[0046]FIG. 1C illustrates a section of a wafer in contact with a sweeperstructure in accordance with the present invention. The sweeperstructure 16AA of the present invention is softer and more flexible thanconventional sweeper structures. Using the sweeper structure 16AA, amore uniform and global contact can be made with the wafer surface. Inother words, the sweeping efficiency is uniform and the force isuniformly distributed. Thus, during use with a low force, typicallyabout or less than 1.0 psi, and preferably less than 0.5 psi or lower,contact can globally occur between the sweeper structure 16AA and thewafer 16, irrespective of whether the wafer 16 is not flat due to bowingof or other stress applied to the wafer as it is being held by a wafercarrier, lack of parallelism between the sweeper and the wafer, ornon-planar topography of the field region.

[0047]FIG. 2A illustrates a more detailed section of a conventionalwafer surface. The wafer substrate 300 includes a patterned layer 302,preferably an insulating layer, formed on a wafer 103 (see FIG. 3A). Thepatterned layer 302 may include an insulator such as a low-k dielectricmaterial and can be formed using well-known patterning and etchingtechniques pursuant to metal interconnect design rules. The patternedlayer 302 can include cavities or gaps, namely the first cavity 306 anda second cavity 308, separated from one another by a field region 310.The cavities can be formed such that the first cavity 306 may be a viaand the second cavity 308 may be a trench having a second via 309. Thevia 306 is defined by a bottom wall 312 a and side walls 314 a. Thetrench 308 is defined by a bottom wall 312 b and side walls 314 b withthe second via 309 defined by a bottom wall 312 c and side walls 314 c.

[0048] One or more thin layers of barrier or glue layer 317 havingmaterials, for example, Ta, TaN, Ti, TiN, or WN coat the cavities aswell as the top surfaces of the substrate 300. A thin film 318 of copperis coated as the seed layer on top of the barrier layer 317 for thesubsequent electroplated copper layer. The copper seed layer 318provides a base for which nucleation and growth of the subsequentdeposition can occur.

[0049]FIG. 2B illustrates the wafer surface of FIG. 2A having a planarcopper layer deposited thereon. A planar copper layer 320 can bedeposited into the cavities 306, 308, 309 and on the field region 310.The deposition process is performed using the present inventiondescribed in greater detail below.

[0050]FIG. 3A illustrates a workpiece-surface-influencing device (WSID)in accordance with the present invention. The WSID 100 is disposed inclose proximity to a workpiece or wafer 103 held by a wafer carrier 105.The wafer carrier 105 is adapted to rotate about the z-axis and move thewafer 103 laterally in the x and y directions. In this embodiment, thewafer carrier 105 is stabilized such that it does not move gimbal duringthe process. During operation, the front surface 104 of the wafer 103 isgenerally perpendicular to the z-axis. Further, FIG. 2A illustrates adetailed illustration of the front surface 104 of the wafer 103. TheWSID 100 of the present invention and the wafer carrier 105 may beimplemented within the conventional ECMPR system 10.

[0051]FIG. 3B illustrates a perspective view of theworkpiece-surface-influencing device in accordance with the presentinvention. The WSID 100 includes a top layer 100 a, an intermediatelayer 100 b, and a bottom layer 100 c. In this embodiment, the top layer100 a may be a thin flexible film that is attached to the intermediatelayer 100 b. The top layer 100 a may be a single layer or a compositelayer (i.e., more than one layer). For example, if the top layer 100 aincludes more than one layer, the layers may not be the same size.However, the total thickness of such composite layers should be lessthan 0.5 mm, and preferably less than 0.2 mm. For example, FIG. 3Dillustrates a composite layer structure 170 of the WSID. The compositelayer structure 170 includes an upper layer 172 and a lower layer 174.In this example, it is desirable that the upper layer 172 be abrasive.

[0052]FIG. 3C illustrates the workpiece-surface-influencing deviceduring operation in accordance with the present invention. Referring nowto FIGS. 3A-3C, the intermediate layer 100 b is compressible and softand attached to the top section of the bottom layer 100 c. The bottomlayer 100 c is a support layer, which is sufficiently rigid to supportthe intermediate layer 100 b and the top layer 100 a. The bottom layer100 c can be a porous plate and can include openings 107 to allow theelectrolyte solution and electric field to freely flow towards thesubstrate surface. In some embodiments, the bottom layer 100 c can be anelectrode. During operation, an electrolyte solution 108 containing theionic species of the metal to be deposited and additives for qualityfilm formation makes contact with the electrode and the wafer surface104.

[0053] The top layer 100 a is a flexible layer that has a thickness ofless than or equal to about 0.5 mm, and preferably less than or equal toabout 0.2 mm. The top layer 100 a may have relatively flat surface suchas the lapping films containing 0.05-0.5 micron size abrasive particles(available from e.g. Buehler or 3M companies), or small diameter postswith flat tops or pyramidal posts such as those employed in fixedabrasive pads provided by 3M company. The surface of the top layer 100 ais preferably abrasive to efficiently sweep the surface of the wafer.Flexibility of the top layer 100 a is critical. In other words, the toplayer 100 a should be flexible enough to fully conform to the wafersurface even if the wafer surface is not absolutely flat as illustratedin FIG. 1C.

[0054] The top layer 100 a also includes openings or channels 116, whichmay have any form or size for uniform copper deposition on the wafer103. The openings 116 can have any shape so long as they allow fluid toflow between the wafer 103 and the electrode (not shown) through theWSID 100. Although the WSID 100 illustrated in FIGS. 3A and 3B has arectangular shape, it may be shaped in many other geometrical shapessuch as a small-area sweeper disclosed in the U.S. patent applicationSer. No. 09/961,193, filed on Sep. 20, 2001, entitled “Plating Methodand Apparatus for Controlling Deposition on Predetermined Portions of aWorkpiece”, and commonly owned by the assignee of the present invention.

[0055] The intermediate layer 100 b is made of a foam or gel-typematerial, which is easily compressible under an applied force, butretains its original shape once the force unapplied. Examples of suchmaterials can be polyurethane, polypropylene, polyethylene, rubber,ethyl vinyl acetate, polyvinyl chloride, polyvinyl alcohol, ethlenepropylene diene methyl, combinations thereof, and the like. Theintermediate layer 100 b may include many interconnected open porenetworks, which allow electrolyte to percolate through them in thedirection of the arrows 108. In this embodiment, the intermediate layer100 b includes an open pore structure. The compression strength of theintermediate layer 100 b should be such that the layer 100 b cancompress about 25% under a testing force of about 1-10 psi, whichtesting force will go above the low force that is used during theprocesses of the present invention.

[0056] During operation, the intermediate layer 100 b should compress byan amount less than 2 mm, but preferably less than 1 mm so that in casethe wafer holder is moved in either x or y direction, the edge of thewafer does not damage the top layer 100 a. Therefore, the thickness ofthe intermediate layer 100 b should be selected accordingly. Forexample, for a compression of 1 mm during operation, if a foam withcompression strength (for 25% deflection) of 1 psi is selected, thethickness of the intermediate layer 100 b should be about 4 mm, if apressure of 1 psi is desired. However, since lower pressures arenormally desired in low-force ECMD process, the thickness of the foam istypically larger (in this example it may be 10-20 mm) or the foamselected typically has lower compression strength. The relationshipbetween the force exerted by the intermediate layer 100 b onto the wafersurface and the compression amount (shown as “d” in FIG. 3C) issubstantially linear with force increasing linearly with the level ofcompression for a given foam, although it may be non-linear.

[0057] As previously mentioned, the exemplary ECMPR system 10 is capableof performing planar or non-planar plating as well as planar ornon-planar electroetching. In this respect, if non-planar process isdesired, the wafer surface 104 can be brought near the top layer 100 aof the WSID 100, but no contact is preferably made so that non-planarmetal deposition can occur.

[0058] Further, if planar process is desired, the wafer surface 104makes contact with the top layer 100 a as a relative motion isestablished between the top layer 100 a and the wafer surface 104. Asthe solution, depicted by arrows 108, is flowed through the open poresof the intermediate layer 100 b and the channels 116 through the toplayer 100 a, the wafer 103 is moved, i.e., rotated and/or laterallymoved, while the wafer surface 104 makes contact with the top layer 100a. Under an applied potential between the wafer 103 and an electrode,and in the presence of the solution that flows through the WSID 100,metal such as copper is plated on or etched off the wafer surface 104,depending on the polarity of the voltage applied between the wafersurface and the electrode. As the top layer 100 a makes contact with thewafer 103, the top layer 100 a conforms to the wafer surface 104 andprovides uniform contact and pressure.

[0059] As described earlier, the low-k dielectrics are not mechanicallystable and may not withstand high compressive forces such as above 1 psiduring the process. Due to the compressibility of the WSID 100, lesspressure can be applied in a uniform manner on such low-k interlayersduring planar deposition of copper layers. As shown in FIG. 3C, as thewafer 103 is brought in contact with the top layer 100 a, the forceapplied on the wafer 103 may be controlled by compressing theintermediate layer 100 b towards the bottom layer 100 c. As indicatedabove, the force exerted onto the wafer surface increases with increased“d.” Due to the flexibility of the top layer 100 a and thecompressibility of the intermediate layer 100 b that is supporting thetop layer 100 a, the WSID 100 is globally and locally flexible. Thisstructure allows locally and globally uniform and low pressure contactbetween the front surface of the wafer and the flexible top layer 100 a.The global and local contact stages between the WSID 100 and the wafer103 may occur simultaneously.

[0060] Referring again to FIG. 3C, as the wafer carrier 105 is loweredtowards the WSID 100, the WSID 100 is first compressed with the wafercarrier 105 moving downwardly. The wafer carrier 105 flexes the toplayer 100 a and compresses the intermediate layer 100 b. At this point,an instantaneous uniform global contact may be established between thetop layer 100 a. Then, as the intermediate layer 100 b tries to recoverback to its original shape, the intermediate layer 100 b applies acounter force to the wafer 103 through the top layer 100 a. As beingpositioned between these two oppositely acting forces, the top layer 100a conforms or locally contacts the wafer surface 104 during thisprocess.

[0061] For the purpose of clarification, the above described processrequires two stages. It is understood that the local contact between thewafer surface 104 and the top layer 100 a may be established in asimultaneous fashion as the wafer carrier 105 is pushed towards the WSID100. Also, as to the low pressure aspect of the process, as the wafer103 is brought into contact with the WSID 100, the force applied by thewafer 103 causes the WSID 100 to compress by an amount “d.” Because thewafer carrier 105 is stabilized, as it is moved, i.e., rotated andlaterally moved, on the WSID 100, “d” does not vary. If “d” is small,the force applied onto the wafer surface by the WSID 100 will also besmall. As “d” increases, force will get larger and larger. By choosingthe compression strength of the intermediate layer 100 b and thedistance “d” the wafer is pushed against the top layer 100 a, any amountof pressure in the range of 0.01-1 psi or higher can be applied to thewafer surface in a uniform manner. As previously mentioned, thepreferred value of “d” is less than 1 mm, since if “d” is too large andthe wafer in FIG. 3C is translated in lateral direction, the edge of thewafer would move against the surface of the flexible layer 100 a andeventually cause damage. Therefore, it is preferred to select thecompressibility value for the compressible layer 100 b such that thedesired pressure or force applied to the wafer surface results in thedistance “d” to be less than 2 mm.

[0062] The wafer carrier 105 used in this example is stabilized and doesnot gimbal during the process. Using a gimbaling head structure such asthe one described in U.S. patent application Ser. No 09/472,522 filed onDec. 27, 1999, entitled “Work piece Carrier Head for Plating orPolishing,” the present invention can be practiced by loading a wafer onthe gimbaling head and applying a predetermined pressure on thechuck-face holding the wafer. The wafer is then lowered towards the WSID100 and pushed against the top layer 100 a until gimballing actionbecomes operable. In this case, the force on the wafer surface isdetermined by the pressure applied onto the gimballing chuck by thewafer carrier 105. The flexible and compressible nature of the WSID 100allows low pressures in the range of 0.01-1 psi be applied withoutloosing uniform contact between the wafer surface and the surface of thetop layer 100 a.

[0063]FIG. 3E illustrates another example of a wafer carrier inaccordance with the present invention. The wafer carrier 605 is similarto wafer carrier 105 except that wafer carrier 605 includes a coilmechanism 610. The coil mechanism 610 ensures that a constant anddesired low pressure is applied to the wafer. For example, when the WSID600 is more rigid, the wafer carrier 605 having coil mechanism 610enables a constant and desired low force to be applied to the wafer.Also, using the wafer carrier 605, the WSID 600 conforms to the wafersurface, as described above. As an example, if the WSID 600 (i.e., pad)is rated at 1-2 psi, then the coil mechanism 610 rated at less than 0.5psi can be used such that a low force transferred to the carrier head605 is also less than 0.5 psi. The coil mechanism 600 should allow thecarrier head 605 to move principally in the vertical direction(z-direction).

[0064]FIG. 4 illustrates another example of aworkpiece-surface-influencing device in accordance with the presentinvention. The WSID may be configured in different forms and shapes. Forexample, a WSID 150 includes a first compressible layer 152 and a secondcompressible layer 154. The compressible layers 152, 154 may be made ofa spongy material having open pore structure. In this embodiment, arigid support layer 155 having openings 155 a is interposed between thefirst and second compressible layers 152, 154. The openings 155 a allowan electrolyte solution to flow from the second compressible layer 154to the first compressible layer 152. The support layer 155 supports theWSID 150 and allows it to collapse uniformly when the wafer is pressedagainst it. As in the previous embodiment, the WSID 150 includes a topflexible layer 156 that is attached to the top of the first compressiblelayer 152. The flexible layer 156 sweeps the wafer surface during theplating process. Openings 158 in the flexible layer 156 allowelectrolyte to flow from the first compressible layer 152 towards thewafer. It should be noted that two or more compressible layers and oneor more support layers may be used herein. As the structure becomesthicker and thicker, it becomes softer and softer. In other words, whenthe wafer is pushed against the WSID 150 by a fixed distance “d”,thicker stacks of compressible layers of a given type yield lower forceon the wafer surface

[0065]FIGS. 5A and 5B illustrate yet another example of aworkpiece-surface-influencing device in accordance with the presentinvention. The WSID 201 includes a compressible layer 200 havingchannels 202 extending from a top surface 203 to a bottom surface 204 ofthe compressible layer 200. Although in this embodiment the compressiblelayer 200 may preferably be made of a closed-pore spongy material sothat an electrolyte can be flowed through the channels 202, it can alsobe made of an open pore spongy material. A flexible layer 206 isattached to the top surface 203 of the compressible layer 200 while asupport plate 208 is attached to the bottom surface 204. The channels202 are continuous through the flexible layer 206 and the support plate208. The flexible layer 206 may include a flexible fixed abrasive layer.The combination of both the flexible nature of the flexible layer 206and the compressibility of the compressible layer 200 allows the waferto establish uniform global and local contact with the WSID 201.

[0066] During operation, as shown in FIG. 5B, the carrier head lowersthe wafer 103 against the WSID 201. The pressure applied by the wafer103 causes the WSID 201 to decrease by distance “d”. As in the previousembodiment, as “d” increases, or the WSID 201 continues to be presseddown, the pressure on the wafer surface increases. The channels 202 aredesigned to assure uniform deposition on or etching from the wafersurface. Again, as in the previous embodiments, the flexible layer 206may be a composite layer of two or more layers.

[0067] The WSID 201 may be configured in different forms and shapes. Forexample, FIG. 6 illustrates still another example of theworkpiece-surface-influencing device in accordance with the presentinvention. The WSID 220 includes a first compressible layer 222 and asecond compressible layer 224. The compressible layers 222, 224 may bemade of a spongy material having closed pore structure. In thisembodiment, a rigid support layer 226 is interposed between the firstand second compressible layers 222, 224. A flexible layer 228,preferably a flexible abrasive layer, is attached on top of the firstcompressible layer 222. Channels 230, which are formed through thelayers 226, 224, 222 and 228 allow an electrolyte solution to flowthorough the WSID 220. The support layer 226 supports the WSID 220 andallows the WSID 220 to collapse uniformly when the wafer is pressedagainst it. More layers of compressible material and support materialmay also be used in such structure.

[0068]FIGS. 7A and 7B illustrate yet another example of aworkpiece-surface-influencing device in accordance with the presentinvention. The WSID 300 is positioned in close proximity to theworkpiece or wafer 103 held by the wafer carrier 105, which has similarcharacteristics as mentioned above. The WSID 300 includes a top layer306 including a top film 308 and a bottom film 310, an intermediatelayer 312, and a bottom layer 314. In this embodiment, the top film 308and the bottom film 310 are made of thin flexible material layers. Thetop film with an upper surface 315 is attached to a top surface 317 ofthe bottom film 310, which in turn is attached to the top section of theintermediate layer 312. The intermediate layer 312 is placed on thebottom layer 314.

[0069] The top film 308 of the top layer 306 is preferably a flexibleabrasive film (with abrasive surface) to efficiently sweep the wafersurface. Therefore, the top film 308 acts as a sweeper for ECMPR. Thetop film 308 may have a thickness in the range of 0.05-5 mm, preferably0.1-1 mm, and may be a layer with relatively flat surface such as thelapping films containing 0.05-0.5 micron size abrasive particles(available from e.g. Buehler or 3M companies), or small diameter postswith flat tops or pyramidal posts such as those employed in fixedabrasive pads provided by 3M company. The bottom film 310 may be a thinfilm which may be made of Mylar or polycarbonate materials. Thethickness of the bottom film 310 may be 0.01-2 mm depending on theflexibility desired. Flexibility of the top film 308 and hence theflexibility of the attached bottom film 310 are important for thepractice of this invention. In one embodiment, the top layer 106 isflexible enough to fully conform to the wafer surface even if thesurface is not absolutely flat.

[0070] The intermediate layer 312 is a compressible layer havingopenings or channels 321 extending from the bottom layer 314 to toplayer 306. The channels allow process solution to flow through the WSID300 and wet the surface of the wafer. In this embodiment, channels 321are formed as slits between sections 319 of the compressible layer 312.Alternatively, the compressible layer 312 may have an open porestructure allowing fluid to flow between the top layer 306 and thebottom layer 314. The bottom layer 314 is a support layer, which isrigid enough to support the compressible layer 312 and the wholeassembly.

[0071] The bottom film 310 includes a number of openings or channels320. In this embodiment, the channels 320 are formed as parallel slitsbetween strips 322 of the bottom film 310. The channel pattern of thebottom film 310 is preferably the same as the channel pattern of thecompressible layer 314. The top film 308 includes channels 324 which arepreferably formed as slits between strips 326 of the top film 308. Thechannels or slits 324 of the top film 308 may be larger than the ones inbottom film 310. The strips 326 of top film 308 is attached on thestrips 322 of bottom 310 film in a crosshatch or mesh configuration.

[0072] The crosshatch configuration allows for a more rigid and stabletop layer 306 as the top layer 306 makes contact with the wafer 103, andcan be used with our without the low force techniques described herein.In other words, when the top film 308 substantially intersects thechannels 320 of the bottom film 310, this provides for a more rigid toplayer 306. Otherwise, if the top film 308 does not intersect thechannels 320 of the bottom film 310, then the films making up the toplayer 306 can be distorted when it makes contact with the wafer 103.

[0073] Another advantage of the cross hatch structure is that a layerwith the cross hatch structure assists in uniformly distributing thesolution across the wafer surface. The solution flows through thecompressible layer 312 and fills the channels 320 in the bottom film 310and then fills the channels 324 in the top film 308. The processsolution which is instantaneously and continuously held in thesechannels provides an efficient and uniformly distributed solution supplyfor the wafer. Cross hatching and vertically stacked channel networkallows process solution to flow without restriction on the surface ofthe WSID 300.

[0074]FIG. 7C illustrates an example of a top layer structure of theworkpiece-surface-influencing device in accordance with the presentinvention. A top layer 500 includes a top film 502 (also shown in FIG.7D) and a bottom film 504 (also shown in FIG. 7E). FIGS. 7D and 7Eillustrate top and bottom films, respectively, of the top layerstructure of FIG. 7C. In particular, the top film 502 includes slantedstripes 506 and straight stripes 508. The straight stripes 510 arelocalized at two non-adjacent corners 510A and 510B of the top film 502.By using straight stripes in the corners 510A, 510B, this designprevents any stripe that may be tangent to the edge of the wafer carrier105 from side-wise engagement to the leading edge of the wafer carrier105 as it moves laterally. The bottom film 504 also contains straightstripes and the slanted stripes to maintain cross hatch configuration ofboth layers. FIG. 7E is also the top view of the compressible layer.

[0075] FIGS. 8A-8C illustrates an example of a non-uniform layer formedon a substrate using a conventional workpiece-surface-influencingdevice. FIG. 8A illustrates a substrate 400 having features 402 formedin an insulating layer 404. The substrate 400 has a non planar surface406 that includes raised regions 408 and recessed regions 410. Such nonplanarity may be due to the various factors including non-idealprocessing conditions performed prior to the copper deposition processstep. The surface may have defects that may cause this non-planarity.Further, a small imperfection or insignificant non-planarity may beaccentuated during the subsequent processing steps, that may involvedeposition of multiple layers, and results in a significantnon-planarity problem. Further, the surface 406 may represent a surfacethat has already received at least one layer of interconnect structure.Non-planarity may result in wafer carrier related problems as well, suchas defective chuck face, o-rings, vacuum system problems or mechanicalproblems. For example, the chuck face on which the substrate is placedmay be defective, or the substrate may be placed on a defective o-ringsthat may cause non-planarity.

[0076] Next, FIG. 8B illustrates a conventionalworkpiece-surface-influencing device 412 making contact with thenon-planar surface 406 during the ECMD copper deposition. As shown,although the raised regions touches the device 412, the recessed regionscannot make contact with the device 412, thereby leaving a gap betweenthe recessed regions 410 and the device 412. As shown in FIG. 7C, as theprocess is carried out, the gap 414 cause a copper film 416 withnon-uniform thickness.

[0077]FIG. 8D and 8E illustrates an example of an uniform layer formedon a substrate using a workpiece-surface-influencing device of thepresent invention. As shown in FIG. 8D, the WSID 418 of the presentinvention conforms with the recessed regions 410 as well as the raisedregions 408 during the process, and hence fully contacts the surface406. In FIG. 8E, under these conditions, copper is deposited over thesubstrate surface to form a uniform layer 420.

[0078] Although various preferred embodiments have been described indetail above, those skilled in the art will readily appreciate that manymodifications of the exemplary embodiment are possible withoutmaterially departing from the novel teachings and advantages of thisinvention.

What is claimed:
 1. A system for uniformly distributing an applied lowforce during processing the workpiece surface using an electrochemicalmechanical process with a solution applied to the workpiece surface anda potential difference between an electrode and the workpiece surface,the system comprising: a workpiece carrier for holding the workpiece inposition during the electochemical mechanical processing; and aworkpiece-surface-influencing-device (WSID) for uniformly distributingthe applied low force to the conductive top surface of the workpiece,the WSID including a compressible material adapted to cause a topsurface of the WSID to conform to the conductive top surface of theworkpiece when contact and relative motion occurs between the topsurface of the WSID and the conductive top surface of the workpiece. 2.The system according to claim 1 wherein the WSID includes a flexible toplayer as the top surface; a rigid bottom layer; and a compressibleintermediate layer containing the compressible material disposed inbetween the flexible top layer and the rigid bottom layer.
 3. The systemaccording to claim 2, wherein the workpiece carrier is adapted to rotatethe workpiece during processing.
 4. The system according to claim 3,wherein the workpiece carrier is adapted to laterally move the workpieceduring processing and the applied low force is less than about one poundper square inch.
 5. The system according to claim 2, wherein theflexible top layer comprises a single layer.
 6. The system according toclaim 2, wherein the flexible top layer comprises a composite layer. 7.The system according to claim 6, wherein the composite layer includes anupper layer and a lower layer, and wherein the upper layer includes anabrasive disposed therein.
 8. The system according to claim 6, whereinthe thickness of the composite layer is less than 0.5 mm.
 9. The systemaccording to claim 2, wherein the rigid bottom layer supports theflexible top layer and the compressible intermediate layer.
 10. Thesystem according to claim 2, wherein the rigid bottom layer, thecompressible layer, and the flexible top layer each include a pluralityof openings through which the solution can pass.
 11. The systemaccording to claim 10 wherein the plurality of openings in thecompressible layer form a plurality of channels.
 12. The systemaccording to claim 11 wherein at least some of the plurality of channelsare parallel to each other.
 13. The system according to claim 12 whereinthe flexible top layer further includes another plurality of channels inwhich at least some of the plurality of channels intersect with at leastsome of the another plurality of channels in a cross hatchconfiguration.
 14. The apparatus according to claim 13 wherein theflexible top layer includes a top film and a bottom film, with the topfilm including an abrasive disposed therein; the another plurality ofchannels are formed in the top film; and the plurality of channels areformed in the bottom film.
 15. The system according to claim 14 whereinthe another plurality of channels in the bottom film and the anotherplurality of channels in the compressible layer are substantiallyaligned.
 16. The system according to claim 2, wherein the rigid bottomlayer comprises the electrode.
 17. The system according to claim 2,wherein the thickness of the flexible top layer is less than 0.5 mm. 18.The system according to claim 2, wherein the flexible top layer includesabrasive particles disposed therein.
 19. The system according to claim18, wherein the size of the abrasive particles is about 0.05-5.0microns.
 20. The system according to claim 2, wherein the compressiblematerial comprises a foam or a gel.
 21. The system according to claim 2,wherein the compressible material is selected from polyurethane,polypropylene, polyethylene, rubber, ethyl vinyl acetate, polyvinylchloride, polyvinyl alcohol, ethylene propylene diene methyl, orcombinations thereof.
 22. The system according to claim 2, wherein thecompressible intermediate layer includes open pore networks that allowthe solution to pass therethrough.
 23. The system according to claim 2,wherein the compressible intermediate layer is selected such that itwould compress about 25% when a testing force of 1-10 pounds per squareinch is applied.
 24. The system according to claim 2, wherein thecompressible intermediate layer is adapted to compress less than 2 mm.25. The system according to claim 2, wherein the flexible top layercomprises a top film and a bottom film attached to each other.
 26. Thesystem according to claim 25, wherein the top film includes abrasiveparticles therein.
 27. The system according to claim 25, wherein thethickness of the top film is in the range of 0.05-5.0 mm.
 28. The systemaccording to claim 25, wherein the thickness of the top film is in therange of 0.1-1.0 mm.
 29. The system according to claim 25, wherein thetop film contains a plurality of channels and the bottom film containsanother plurality of channels such that the plurality of channels andthe another plurality of channels intersect e each other in a crosshatch configuration.
 30. The system according to claim 1 wherein theWSID includes: at least two compressible layers, with at least one ofthe compressible layers containing the compressible material; a leastone rigid support layer disposed in between the at least twocompressible layers; and a flexible layer attached to one compressiblelayer, wherein the flexible layer makes contact with the workpiecesurface.
 31. The system according to claim 30, wherein the rigid supportlayer supports the flexible top layer and the compressible intermediatelayers and wherein the applied low force is less than about one poundper square inch.
 32. The system according to claim 30, wherein the rigidsupport layer, the at least two compressible layers, and the flexiblelayer each includes openings through which the solution can pass. 33.The system according to claim 32, wherein the flexible layer includesabrasive particles disposed therein.
 34. The system according to claim30, wherein the compressible intermediate layers include open porenetworks through which the solution can pass.
 35. The system accordingto claim 30, wherein the flexible top layer and at least one of thecompressible intermediate layers each include a plurality of channelsarranged in a cross hatch configuration and the other compressible layerand the rigid support layer contain openings of some type through whichsolution can pass.
 36. The system according to claim 1, wherein thesolution comprises an electroplating solution, an electro-etchingsolution or an electro-polishing solution.
 37. The system according toclaim 1, wherein the applied force is less than about 1 pound per squareinch. 38 The system according to claim 1, wherein the applied force isless than 0.5 pounds per square inch.
 39. The system according to claim1, wherein the workpiece carrier includes a coil mechanism.
 40. Thesystem according to claim 1, wherein the WSID includes at least acompressible layer containing the compressible material attached to arigid layer and the applied force is less than 0.5 pounds per squareinch.
 41. The system according to claim 40, wherein the rigid layersupports the compressible layer and a flexible top layer disposed on thecompressible layer.
 42. The system according to claim 1 wherein the topsurface of the WSID has a surface area that substantially covers theentire workpiece except for an edge region.
 43. The system according toclaim 1 wherein the top surface of the WSID has a surface area that issubstantially smaller than a surface area of the top conductive surfaceof the workpiece, and further including a mechanism for moving the WSIDacross the entire top conductive surface of the workpiece.
 44. Aworkpiece-surface-influencing-device (WSID) for uniformly distributingan applied force to a top conductive surface of a workpiece, comprising:a flexible layer adapted to conform to the top conductive surface of theworkpiece as contact and relative movement between the top conductivesurface of the workpiece and the flexible layer occurs; a compressiblelayer adapted to absorb the applied force and assist in providinguniformity in the applied force to the entire top conductive surface ofthe workpiece that is contacted by the flexible layer; and a rigid layeradapted to support the flexible and compressible layers, wherein each ofthe flexible layer, the compressible layer, and the rigid layer providea unitary structure that uniformly distributes the applied force to thetop conductive surface of the workpiece.
 45. The WSID according to claim44, wherein the flexible layer comprises a composite layer including anupper layer and a lower layer, with the upper layer including anabrasive disposed therein.
 46. The WSID according to claim 45, whereinthe upper layer and the lower layer each contain a plurality of channelsarranged in a cross hatch configuration.
 47. The WSID according to claim44, wherein the compressible layer, the flexible layer, and the rigidlayer each includes openings that allow a solution to pass therethrough.48. The WSID according to claim 47 wherein the plurality of openings inthe compressible layer form a plurality of channels.
 49. The WSIDaccording to claim 48 wherein at least some of the plurality of channelsare parallel to each other.
 50. The WSID according to claim 49 whereinthe flexible layer further includes another plurality of channels inwhich at least some of the plurality of channels intersect with at leastsome of the another plurality of channels in a cross-hatchconfiguration.
 51. The WSID according to claim 50 wherein the flexiblelayer includes a top film and bottom film, with the top film includingan abrasive disposed therein; the another plurality of channels areformed in the top film; and the plurality of channels are also formed inthe bottom film.
 52. The WSID according to claim 44, wherein the rigidlayer comprises an electrode.
 53. The WSID according to claim 44,wherein the flexible layer includes abrasive particles disposed therein.54. The WSID according to claim 44 wherein the compressible layerincludes a plurality of compressible layers.
 55. The WSID according toclaim 54 wherein the flexible layer includes a plurality of flexiblefilms.
 56. The WSID according to claim 55 wherein the rigid layerincludes a plurality of rigid layers.
 57. The WSID according to claim 54wherein the rigid layer includes a plurality of rigid layers.
 58. TheWSID according to claim 44 wherein the compressible layer includes openpore networks that allow a solution to pass therethrough.
 59. The WSIDaccording to claim 44 wherein the compressible layer is adapted tocompress about 25% when a testing force of 1-10 pounds per square inchis applied.
 60. The WSID according to claim 44, wherein the compressiblelayer is adapted to compress less than 2 mm.
 61. The WSID according toclaim 51, wherein the top film and the bottom film are attached to eachother in a cross hatch configuration.
 62. A method for uniformlydistributing an applied low force to a workpiece having a top conductivesurface using a workpiece carrier and aworkpiece-surface-influencing-device (WSID) during processing of the topconductive surface of the workpiece, the method comprising: supportingthe workpiece on the workpiece carrier so that the top conductivesurface can be processed; during processing, causing the workpiececarrier and the WSID to move in relation to each other and the topconductive surface of the workpiece and a top surface of the WSID tocontact; and while the step of causing is occurring, applying theapplied low force on the top conductive surface of the workpiece usingthe WSID, such that the top surface of the WSID conforms to the topconductive surface of the workpiece.
 63. The method according to claim62 further comprising flowing a solution to the workpiece surfacethrough the WSID.
 64. The method according to claim 63, wherein thesolution comprises an electro-plating solution, an electro-etchingsolution or an electro-polishing solution.
 65. The method according toclaim 62, wherein the applied low force is used to compress the WSIDabout 25%.
 66. The method according to claim 62 wherein the applied lowforce is less than about one pound per square inch.
 67. The methodaccording to claim 62 wherein the applied low force is less than about0.5 pounds per square inch.
 68. A workpiece-surface-influencing-device(WSID) for distributing solution to a workpiece surface of a workpiecewhile the WSID and the workpiece surface move relative to each other,the WSID comprising: a bottom portion having a plurality of channelsthat are substantially parallel to each other; a top portion havinganother plurality of channels that are substantially parallel to eachother, such that the plurality of channels and the another plurality ofchannels intersect in a cross-hatch configuration to cause distributionof the solution to the workpiece surface to occur more uniformly. 69.The WSID according to claim 68 wherein the top portion is thinner thanthe bottom portion.
 70. The WSID according to claim 69 wherein the topportion and the bottom portion are separate top and bottom layers,respectively.
 71. The WSID according to claim 70 wherein the bottomlayer contains a compressible material so that the bottom layer iscompressible and will allow the WSID to conform to the workpiecesurface.
 72. The WSID according to claim 71 wherein the bottom portionfurther includes another flexible layer disposed between the bottomlayer and the top layer, and the another flexible layer contains afurther plurality of channels that are aligned with the plurality ofchannels.
 73. The WSID according to claim 69 wherein the top and thebottom layers are adhered to one another.
 74. The WSID according toclaim 69 wherein the top and the bottom layers are not adhered to oneanother.
 75. The WSID according to claim 69 wherein the top layerincludes an abrasive disposed therein.
 76. The WSID according to claim69 wherein the